Integrated circuit devices frequently utilize active and passive devices to achieve desired operating characteristics. Typical passive devices include capacitors, resistors and inductors. Many techniques have been developed to form resistors having different resistance values and some of these techniques include using different materials having different resistivities and different dimensions. One such technique, which is disclosed in U.S. Pat. No. 6,548,851, includes forming a resistor in a peripheral circuit area of a semiconductor substrate. This resistor is formed from the same material used to define an upper capacitor electrode in a memory cell array area of the substrate. U.S. Pat. No. 6,730,573 discloses forming a resistor from a metal layer that is also used to define an upper capacitor electrode. U.S. Pat. No. 6,040,596 discloses a resistor formed from the same material as an upper plate electrode of a memory cell capacitor. Conventional techniques for forming resistors are also disclosed in U.S. Pat. Nos. 4,643,777 and 6,211,031.
Notwithstanding these conventional techniques for forming resistors, there continues to be a need for improved methods of forming resistors on integrated circuit substrates.